CIB2 and Usher syndrome type 1: To date, six CIB2 missense mutations (Fig. 8b, top) causing Usher syndrome type 1 (p.E64D) and non-syndromic hearing loss (p.R66W, p.F91S, p.C99W, p.I123T, p.R186W) have been reported in humans19, 29, 32.